There are known control valves adapted to gas heating appliances that include a pilot flame, such as water heaters, dryers, etc. The control valves comprise an electromagnetic safety valve that is housed in a body of the control valve and which closes the passage of gas in the event of the pilot flame being extinguished, and a thermocouple heated by a flame that generates an electrical current for operating the electromagnetic safety valve, keeping it energised while the pilot flame heats the flame thermocouple.
Such a control valve typically comprises an electrical switch as an additional safety element that acts on the electromagnetic safety valve when the water temperature in the gas heating appliance exceeds a certain temperature, cutting off at that point the supply of power to the safety valve. As the electromagnetic safety valve is not energised, it closes the passage of gas towards a burner of the heating appliance, regardless of whether the pilot flame remains lit.
In the prior art the use of electrical switches of the bi-metallic type is known, these being switched off if a certain temperature is exceed.
In addition, during the last few years a control valve which comprises an electrical switch of the butterfly type has been used which presents, among other drawbacks, problems with regard to the stiffness of the connections as well as assembly problems. In these types of control valves the electromagnetic safety valve is fixed by being threaded into the interior of a body of the control valve, with a subsequent reduction of both manufacturing and assembly costs.
For the purposes of solving the problems of control valves with a butterfly-type electrical switch, U.S. Pat. No. 7,073,526 B2 discloses a gas control valve that comprises a valve or electromagnetic unit, a spacer, a retention member that is threaded onto the body of the control valve to hold the electromagnetic valve and the spacer in the interior of the body, and a connector designed to be coupled to the spacer from the exterior of the control valve once the electromagnetic valve, the spacer and the retention member have been assembled on the control valve.
Finally, U.S. Pat. No. 3,654,591 describes a gas control valve that comprises an electromagnetic valve, an electrical switch that comes into contact with the electromagnetic valve, a thermocouple, and a retention member that holds the electromagnetic valve and electrical switch in the interior of the body of the control valve. The electrical switch comprises a substantially cylindrical insulating body and electrical connection terminals for the electrical connection to the electromagnetic valve and the thermocouple, where flexible electrical cables are respectively fixed.